Electric terminal block assembly



Jan. 12, 1954 A. G. COOK ELECTRIC TERMINAL BLOCK ASSEMBLY Filed July 50, 1951 Patented Jan. 12, 1954 UNITED STATES PATENT OFFICE ELECTRIC TERMINAL BLOCK ASSEMBLY ArnoldGJCcdk, Lombard, Ill.,- assignor to General iiElectticfGompany a corporation ofiNew York 9-5 Claims. '1

This invention relates to fan? improvedterminal block assembly.

Frequently, electric terminal blocks "must ,be located in confined spaces in.which it'is difficult to manipulate the electrical" leads .and the usual terminal. screws "by which th leads;are connected to the contactimembers. Inelectric'range ovens, for example, there are provided one or more termina1"blocks=mounted 'on'ithe .rear oven wall. These terminalibl'ocks' have spring contacts receptive to blade-liketerminals projecting from an oven heating .unit,'andpermit'theiheating unit to be removedfromtheovenwhenthe oven wall below; the :unit, orthef unit itself; is f'to j be cleaned, or the. unit shiftedto another .elevation within the oven as;is"no.w thepractice in some range constructions. The heating unit terminal blade and contact c'lipsiofthe terminalblock are sized for very tight engagement. It is necessary therefore to securethe contact clip against being pushed or pulled Withinlthe terminalphousing as the oven unit islinsertedfor removed.

In the usual production 'line manufacturing operation it. is advantageous'to complete'the assembly of therangebodyand casing and then make up .the. electrical nonnections. (Because of the location of "the Ioven terminal iblo'cks, the cramped "space and 'unha'ndy access, it .has been rather "difficult and"'time=consum ing"'to "attach the oven circuit conduc'torstoterminal blocks in Whichthe 'contactclips wereilxedlysecured within the housing. Constructions have'been proposed bywhich the'circuit conductorsmay'be attached before theclip is insertedintothe housing, but although electrically "adequate, they 'have been subject to various "servicing difliculties.

It is therefore aprincipal obj ect of-this invention to provide a terminal 'block in which the contact clips may be preassembIed to the' lead wires andinserted mto the-housing-throu'gh a rear opening, saidclips' having means-which hold securely against accidental displacement within the housing while being easily releasabletqpermit the clips to "be withdrawn foriservicing.

Otherfeaturesandadvantages or'rnyinvcntion will appeanfrom'the following: detailedoescription of a"presently"preferred embodiment read'in conjunction withthe"accompanyingflrawings; in which:

Fig. 1 is *a'fragmentary sidezelevation partly ln-section, of an electricfrange oven? having a terminal block. embodying the, present invention;

"Fig. 215 an 'cnlargedside sectional elevation showing the terminalitblock .withv the, contact'clip in home position and a terminalblade inserted;

Fig.1. As'is well known, an oven comprises a five-sided casing suitably supported within the rangefframe structure. Usually relatively heavy insulation, such as rock wool or the like, surround the cavity, and the hinged door is similar- Iy-insulated. Specifically, Fig. 1 shows the floor 'I of the oven, rear wallZ, side wall 3, door 4, and

a rear panel 5 which constitutes an element of therange frame. With respect to the latter, it LiS DOiIItGd out that present day manufacturing practice for electric ranges and the like utilizes a wrap aroun construction in which the rear panel" 5 is integral with th side and front panels (not shown); An oven heating unit-6 includes a baflle plate 1 suitably supported above the oven floor by a-rear' leg 8 and a front support 9. Sus- "pended beneath the baflle, as by a suitable number ofstraps I0, is a heating element lll,-prefcrably of the well known sheathed coil type. The men heating unit may be of the general type shown in Patents #2,498,583 and 2,536,613 which respectively issued to H. W. Schulze et al. and

H. W. Schulze on, February 21, 1950, and January 2,;1951, and are assigned to my present assignee.

The oven unit isintendedfor easy removal fromthe-oven-and its heating element is proadded with rigid blade-like terminals 12, usually three in number to provide a ground connection. Thes terminal blades releasably engage: contact clips M in aterminalblock l 5 much the same as anyappliance plug cooperates with the usual contact "clips of a convenience outlet. Because of the high wattage of the usual oven unit and the tendency of the unit to walk or work" during heating and cooling'periods, the terminal blades and the-contact clips are sized and arranged for very tight engagement. Thecontact clip is therefore subjected to strong pushing or pulling effort whenthe heatingunit is inserted and removed.

In the usual. electric range the, controls (not shown) are located remote from the various heating units. "The oven control, for example, may

serted and secured within th terminal block ploy a rigid, but flexible, retainer which is of angle form having a short rear wall 31, a relatively long, flexible arm 38, and a finger 39 exhousing after the range structure has been completed.

The terminal block housing may advantageously comprise a, ceramic body .18 having a front flange It which backs up against the front face or" the oven wall 2 for securement thereto by screws 29 or equivalent passing into said wall. As best shown by comparison of Figs. 2 and 4, the body has rather long, rectangular, contactreceiving cavities 2| individual to the respective contact clips 14. Each cavity has a large rear opening 22 providing for the insertion of the contact clip from the rear, as later described. The home position of a contact clip is established by front walls 23 which are actually the rear walls of a cruciform passage having a horizontally arranged slot-like opening 24 through which the blade 12 may be inserted, and upper and lower grooves 25, each of which terminates in an abrupt wall 23. Cavities 21 are characterized by upper and lower pairs or" walls 2! which reach inwardly from the respective side walls 23 toward a centrally disposed narrow groove 29, the base 36 of which slopes toward the front of the housing to a point at the same level as that of the walls 21. The base wall 33 of each groove terminates abruptly at the vertical wall 23. The upper and lower grooves 25 and 23 are in alignment and are preferably of the same width; at least, groove 25 should not be narrower than groove 29. The groove 25 forms a pocket for the reception of a detent finger, as later explained.

It will be observed that the various walls defining the grooves and body cavities are symmetrical. This is merely to facilitate installation of the terminal block by making it unnecessary to distinguish between top and bottom sides thereof.

The contact clip 14 is itself of relatively conventional pattern, being formed from a single piece of suitable spring metal stock, such as strip steel suitably heat treated and silver plated. The

rear wall 3| is tapped to receive a terminal screw 32. Forwardly of said rear wall are short shoulder portions 33 from which extend the contact elements 34 which converge to a normally closed throat 35 and then diverge to provide a mouth for the reception of a terminal blade l2. It will be noted that the extremities of the contact ele-' ments, have a forwardly projecting tongue 33 which fits within the respective upper and lower grooves 25, and thus keep the mouth of the contact clip centered with respect to the entrance slot 24. y

It is readily apparent from Figs. 2 and 4 that the clip I4 will be supported within the cavity 2| by the upper and lower pairs of walls 21, and that the front walls 23 prevent the contact clip from being drawn forwardly out of the terminal block. However, means must be provided to secure the clip from being driven rearwardly out of the open end of the terminal block so that the blade l2 may be inserted. Accordingly, I. em.-

tending upwardly from the end of said arm 38. Rear wall 31 has an aperture 40 to permit the passage of the terminal screw 32. The arm 38 and rear wall 31 are preferably in rectangular relationship. When the retainer is placed over the contact clip and the screw tightened, rear wall 3! will be clamped against wall 3| and the arm 38 will lie on the adjacent shoulder 33. In such position the spacing between the upper edge of finger 39 and the plane of the bottom shoulder 33 is greater than the maximum spacing between the upper and lower walls 21, and hence as the assembled v.contact clip is installed the sloping wall 30 will engage the finger 39 and flex the arm 38 downwardly.

In application, the bared end of conductor I6 is looped about the shank of screw 32, the retainer placed with its 'wall 3'! adjacent the rear wall 3| of the contact clip, and the screw made up tight. This preassembly may be made by unskilled workmen. A range assembler takes the preassembly (usually he receives them in suitable groups of three in which the conductors are tied or taped together) and runs or fishes the wires within the space at the rear of the range and exposes the contact clip portions at the opening l1. Another assembler along the production line then grasps the contact clip and inserts them into the respective cavities 2|. To facilitate this operation, the terminal block housing and contact clip are sized and arranged so that finger 39 will enter the slot 29 while there is still a substantial portion of the terminal clip outside of the rear plate 3. Then the operator pushes the contact clip forwardly to its home position in the terminal housing. The arm 33 flexes downwardly and as the finger 39 passes the wall 26. which coincides with the attainment of home position, the arm snaps upwardly to the Fig. 2 position. The contact clip then is secure against being driven rearwardly by the pressure of the terminal blade as it is being inserted. As the blade [2 enters the throat, the tendency of the shoulders 33 to separate is resisted by the springlike arm 38, with the result that the jaw pressure on the terminal blade is somewhat increased and the electrical contact pressure between the terminal bladeand contact clip is improved.

A substantial advantage of my construction lies in the ease with which the contact clip may be removed. No probes or special tools to depress the arm 39 are required. It is only necessary to unscrew terminal screw 32 until its head has been backed away sufiiciently for the retainer to fall of its own weight until the finger 39 has dropped below wall 26 as shown in Fig. 3. Then the mechanic or repairman may pull the entire contact clip assembly out of the housing. It will be apparent that the center of gravity of the retainer is to the left of the contact clip shoulder portion (as viewed in Fig. 3) and that it will ordinarily rotate into release position. If it should stick or bind, a light touch with the screw driver blade will free it. It will also be apparent that the lift of the rear wall 31 necessary to remove the finger 39 from the pocket 25 is small. Therefore, opening 45 need be only slightly larger than the diameter of the shank or screw 32'to permit such movement and the danger of the bared end of conductor [6 jamming within opening Wis eliminated.

While there has been described what is at present considered to be the prefer'r'edembodi ment ofthe invention, i-twill'be understood that various modifications-may be made therein, and it is intended to cover in the appended claims all such modifications as fall within the true spirit and scope of the-invention.

1-. Electric terminal means comprising in combination, a housing having wall means defining an elongated cavity open at the front and at the rear, a contact clip adapted to be manually insertedinto said cavity; said contact clip having elongated contact elements reaching forwardly within said cavity and terminating in a throat facing said front opening, a retainer having a resilient" arm member adapted to extend along one of said contact elements in overlying relation therewith, one end of said arm member having a fingerextending angularly therefrom, terminalscrew means for removably securingthe opposite end of said arm member to said contact clip, wall means within said. cavity establishing a home position for said contact clip therein, means for placing the resilient arm member of, said, retainer under stress as the contact clip, and, thereto affixed retainer are inserted into said cavity, wall means defining a pocket adapted to receive said finger by reaction of said arm member as said finger passes said wall means substantially coincident with the attainment of home position by said contact clip, said finger and said wall means thereafter cooperating to hold the clip against withdrawal from said cav ity, and means elfective upon loosening of said terminal screw means to permit said retainer arm member to rotate relative to said contact clip to remove said finger from said pocket.

2. Electric terminal means comprising in combination, a housing having wall means defining an elongated cavity open at the front and at the rear, a contact clip adapted to be manually inserted into said cavity, said contact clip having elongated contact elements reaching forwardly into said cavity and terminating in a throat facing said front cavity opening, means engageable with the forward ends of said contact elements to establish a home position of said contact clip Within said cavity, and a retainer releasably secured to said contact clip, said retainer having a resilient arm member extending along one of said contact elements in spaced relation therewith, said arm member having a finger extending an gularly therefrom, wall means within said cavity engaging said finger to fiex said arm member downwardly as said contact clip is inserted into said housing, said wall means terminating in other Wall means establishing a pocket which said finger may enter by reaction of said flexed arm member as said contact clip attains home position, said last-named wall means and said finger thereupon cooperating to secure said contact clip against withdrawal from said housing; the se-' curement means for said retainer comprising a terminal screw passing freely through said retainer and entering said contact clip to fix said retainer securely thereto for operation of the arm member into said contact clip securing position upon being tightened, and releasing said retainer for free rotation of its arm member out of such position upon said retainer being loosened from said contact clip.

3. Electric terminal means comprising in combination, a housing having wall means defining an elongated cavity open at the front and at the rear, a contact clip adapted to be manually inof said arm member having a finger extending angularly therefrom; terminal screw means for removably securing the opposite end of said arm member to said contact clip, wall means within said cavity establishing a home position for said contact clip therein, wall mean including awall sloping toward the-forwardend of said housing defining agroove along which said finger may travel, said sloping wall means engaging said finger and flexing saidarm member to place the sameunder stress" as the contact clipand theretoafiixed retainer are inserted into said cavity, wall means at the forward end of said sloping wall defining a pocket adapted to re-, ceive said finger b reactionofsaidarmmember as said finger passessaid last-named wall means substantially coincident with the attainment of home position by. said contact clip, said' finger and said wallmeans thereafter cooperating to hold the clip against withdrawalfrom said cavity, and meanszefiectivesupon loosening of said terminal; screw means to lpermit. said retainer arm member to rotate relative to said contact clip to remove said finger from said pocket.

4. Electric terminal means comprising in combination a contact clip having a rear wall portion and upper and lower contact elements extending forwardly therefrom, a retainer including a short rear wall member adapted to overlie said contact clip rear wall portion and a relatively long, springable, arm member extending angularly therefrom in overlying relationship with one of said contact elements, the free end of said springable arm member having an upstanding finger, means on said contact clip for pivotally supporting said retainer thereon, a terminal screw passing freely through a relatively large opening in said retainer rear wall member and entering said contact clip rear wall to secure said retainer to said contact clip with the retainer rear wall held against rotation relative to the contact clip, a housing having a cavity to receive the assembled contact clip and retainer for manual insertion from the rear, said housing having an opening at the front permitting introduction of a terminal thereinto for engagement with said contact clip, means within said housing establishing a home position of said contact clip therein, wall means in said housing engaging said retainer arm member as the contact clip is inserted into said cavity to deflect said retainer arm member and place the same under stress, and wall means in said housing defining a pocket to be entered by said retainer arm member finger as said contact clip attains home position, said finger and said last-named wall means thereafter cooperating to prevent rearward displacement of said contact clip; the normal clearance between the wall of the opening in said retainer rear wall member and the shank of said terminal screw being such that when said screw is loosened the retainer may under its own weight rotate sufficiently to remove said finger from said pocket to free the contact .clip for withdrawal from said housing.

5. Electric terminal means comprising in combination, a contact clip having a rear wall portion and an upper contact element extending forwardly and downwardly therefrom, a retainer in- 7. eluding a short rear wall member adapted to overlie said contact clip rear wall portion and a relatively long, springable, arm member for extension in overlying spaced relationship with said upper contact member, the free end of said springable arm member having an upstanding finger, shoulder means on said upper contact element establishing a pivot point for said retainer arm member, the center of gravity of said retainer being intermediate said shoulder means and said finger, a terminal screw passing freely through a relatively large opening in said retainer wall member and entering said contact clip rear wall to secure said retainer to said contact clip with the retainer rear wall held against ro tation relative to the contact clip, a housing having a cavity to receive the assembled contact clip and retainer for manual insertion from the rear, said housing having an opening at the front permitting introduction of a terminal thereinto for engagement with said contact clip, means within said housing establishing a home position of said contact clip therein, wall means in said housing above said retainer and engaging said finger as the contact clip is inserted into said cavity to deflect said retainer arm member toward said upper contact member and place the retainer arm member under stress, and wall means in said housing at the end of said fingerengaging wall means and defining a pocket to be entered by said retainer finger as said contact clip attains home position, said pocket permitting said retainer arm member to react upward- 1y, said finger and said last-named wall means thereafter cooperating to prevent rearward displacement of said contact clip; the normal clearance between the wall of the opening in said retainer rear wall member and the shank of said terminal screen being such that when said screw is loosened the retainer may under its own weight rotate sufiiciently to remove said finger from said pocket to free the contact clip for withdrawal from said housing.

, ARNOLD G. COOK.

References Cited in the file of this patent UNITED STATES PATENTS Number 7 Name Date 1,259,612 Friedel Mar. 19, 1918 1,626,580 Finizio Apr. 26, 1927 1,735,731 Cunningham Nov. 12, 1929 2,011,543 Meyer Aug. 13, 1935 2,188,789 Kimball Jan. 30, 1940 2,458,097 Penfold Jan. 4, 1949 

